Traceroute Tool from Scratch in Go
2 days ago
- #ICMP
- #traceroute
- #networking
- Traceroute is a network diagnostic tool that maps the path packets take across an IP network by listing intermediate routers and their hop times.
- ICMP (Internet Control Message Protocol) is the underlying protocol for traceroute, used for diagnostics, control, and error reporting.
- Ping, a common ICMP utility, tests host reachability by sending ICMP Echo Requests and receiving Echo Replies.
- Traceroute works by manipulating the TTL (Time-To-Live) field in IP packets to trigger ICMP Time Exceeded messages from routers.
- Different probe methods (ICMP, UDP, TCP) can be used in traceroute, each with unique ways to confirm destination reachability.
- Traceroute operates at Layer 3 (Network Layer) of the OSI model, leveraging IP and ICMP protocols.
- Asymmetric routing means the return path of packets may differ from the request path, complicating diagnostics.
- A simple traceroute tool can be built in Go using the `golang.org/x/net/icmp` package to send probes and interpret replies.
- Running the Go traceroute requires `sudo` due to the need for raw socket access to listen for ICMP messages.
- Future enhancements for traceroute tools include reverse DNS lookup, ASN lookup, geo-location, concurrency, and multiple probes per hop.